Spiral stairway



July 28, 1925.

E. M cLuRE SPIRAL STAIRWAY Filed Oct. 24', 1924 jfzzwari 11/7/6419 Patented July 28, 1925.

UNITED STATES PATENT 0F'F'ICE EDWARD MCCLURE, or CHICAGO, I'LLrNoIs, ASSIGNOR or ONE-HALF TO FRANKLI'II r. SMITH, OF CHICAGO, ILLINOIS.

SPIRAL STAIRWAY.

Application filed October 24, 1924. Serialdio'; 745,567.

To all whom it may concem: Be it known that I, EDWARD MCGLURE, a citizen of the United States, and a resident of Chicago, Cook County, and State of Illinois, have invented certain new and useful Improvements in SpiralStair-ways,of which the following is declared to be a full, clear, and exactdescription.

This invention relates to spiral Stairways and: its principal object is to provide a spiral; stairway construction inwhich sheet metal treads may be employed, whereby a lighter construction is obtained than with the usual cast iron treads. One object is-to provide means for bracing the outer ends of the treads to thereby hold them in their horizontal position. Another object is to provide a spiral stairway that may be readily as-' semble'd, and in which any tread may" be re moved and replaced without disturbing the remaining treads. With these and other ob jects and advantages" in view, thisinvention' consists in the severalnovel featureshereinafter-fully set forth and claim'ed.

The inventionisclearly illustrated inthe accompanying drawing in which:

Fig. 1' is 'a front elevation-o f'a portion of a spiral stairway embodying a simple form-of the' presentinventiong" Fig. 2 is a side elevation thereof; Fig. 3 is a plan with the central column and railing posts shown in section, and Fig. 4 is a side elevation of one of the rail posts.

Referring to said drawing which illustrates one embodiment of the invention, the reference character 5 designates a column such as is usually used for the centre support of spiral Stairways, said column is shown as of round form although this is immaterial. The treads 6, preferably formed of sheet metal, are secured to and supported by said column, and extend radially therefrom and around about the same in spiral formation. Each tread is approximately shaped in the form of a sector and its side edge portions are bent down to form stiffening and reinforcing flanges 7. Each tread is secured to the column by a clamp collar 8, which is passed about the Column and bolted to one web of a T iron 9 which is secured to the lower side of the tread by bolts, rivets or the like. By drawing up tightly on the bolts of the clamp collar sufficient friction is created between the column and to firmly secure the-tread to the lower end 'portion 14- of each post projects Y below the rear'of the lower tread to which it is secured, and is bent forward at-an ob lique angle and runs to the back of the tread next below, to which it. is also secured by the bolts, ri'vets' or'the like 17 g It" will therefore be seen that each post 10 isbolt ed to 'three'treads, thus-tying them to ther. Furthermore, that the part11- 0 one post, a tread 6' and the oblique part '14 of another post form a triangular truss like" structureof which the front portionis sup-' portedby anupri'ght -part- 11- of-apost, andthe back portion is supported by the diag-' onal or oblique brace like part14 ofan'other post. Any tendency for the sheet metal tread to sa'g either' at the" front or back is wholly eliminated.

The: posts 10 are extended lip-above the parts 11 in the form of railing supportin" posts 16 to which a hand rail 17 is secure' as for instance by clamp collars 18 bolted or otherwise fastened to the upper ends of the posts 10.

It will be observed that a rigid substantial structure is produced, which is light in weight. The treads are braced and tied together in such a manner that the whole structure is rigid throughout. In case it should become necessary to remove and replace any tread, the same may be readily done without disturbing the other treads. The stairway may be erected from the bottom up as the clamp collars may be slipped over the column at any place thereon.

More or less variation of the exact details of construction is possible without departing from the spirit of this invention; I desire, therefore, not to limit myself to the exact form of the construction shown and described, but intend, in the following claims, to point out all of the invention disclosed herein.

I claim as new, and desire to secure by Letters Patent:

1. A spiral stairway, comprising a central column, light metal treads secured thereto and extending radially therefrom inspiral formation, and posts, one secured to the front of each tread, and to the backs of the two treads next below, the part of the post which is secured to said two last mentioned treads extending obliquely between said treads to form a brace therebetween.

2. A spiral stairway, comprising a central column, light metal treads secured thereto and extending radially therefrom in spiral formation, and posts, each having an upright portion secured to the front of one tread and to the back of the tread next below, and each post having an oblique brace portion below said upright portion, running to and secured to the back of the tread next below the lowermost above mentioned 3. A spiral stairway comprising a central column, sheet metal treads radiating therefrom and extending in spiral formation, clamp collars surrounding said column and secured to said treads, and posts, one secured to the front of each tread, and to the backs of the two treads next below, the part of the post which is secured to said two last mentioned treads extending obliquely between said treads to form a brace therebetween.

4, A spiral stairway comprising a central column, sheet metal treads radiating therefrom and extending in spiral formation, clamp collars surrounding said column and secured to said treads, and posts, each having an upright portion secured to the front of one tread and to the back of the tread next below, and each post having an oblique brace portion below said upright portion running to and secured to the back of the tread next below the lowermost above mentioned one.

5. A spiral stairway, comprising a central column, light metal treads secured thereto and extending radially therefrom in spiral formation, and posts, one secured to the front of each tread, and to the backs of the two treads next below, the part of the post which is'secured to said two last mentioned treads extending obliquely between said treads to form a brace therebetween, and

'that part of each post which extends above the uppermost tread to which it is secured forming a hand rail supporting post.

6. A spiral stairway, comprising a central column, light meta-l treads secured thereto and extending radially therefrom in spiral formation, and posts, each having an up right portion secured to the front of one tread and to the back of the tread next below, and each post having an oblique brace portion below said upright portion, running to and secured to the back of the tread next below the lowermost above mentioned one, and that part of each post which extends above the uppermost tread to which it is secured forming a hand rail supporting post.

7. A spiral stairway comprising a central column, sheet metal treads radiating therefrom and extending in spiral formation, clamp collars surrounding said column and secured to said treads, and posts, one secured to the front of each tread, and to the backs of the two treads next below, the part of the post which is secured to said two last mentioned treads extending obliquely between said treads to form a brace therebetwcen, and that part of each post which extends above the uppermost tread to which it is secured forming a hand rail supporting post.

EDWARD MCCLURE. 

